A theatrical milestone was laid last night in a 100-seat theater in Midtown.

National Comedy Theatre, a local improv troupe now in its 14th year, marked its 3,823rd performance — making it the longest continuously running show in San Diego history. The comedy “Triple Espresso” closed in 2010 after 3,822 shows, and before that, “Forever Plaid” ran for six years in Old Town.

But unlike the two stage plays, National Comedy Theatre has achieved its record with very little publicity. For founding artistic director Gary Kramer, NCT’s secret to longevity is a tribute to both the quality of its cast and sheer perseverance: “We’ve got the luxury of being too stupid to close, so we didn’t.”

Early roots

Kramer brought the National Comedy Theatre concept to San Diego in May 1999, after producing a similar improv show in Santa Barbara for nine years. He auditioned and cast 18 local actors, put them into a five-month training program and rented the long-shuttered Marquis Theatre on India Street.

“It had been used as storage, and every type of animal was living in this place, including a lot of the insect kingdom,” he said. With shovels and crowbars, the actors overhauled the Marquis and opened with three shows a week on Oct. 8, 1999.

“It was a slow start, but every month it picked up steadily and kept growing and growing and we were able to start adding shows” he said.

Today, National Comedy Theatre has a cast of 25 actors who alternate in six to eight (mostly sold out) shows a week. It also hosts a college improv team and a high school league, does corporate events, offers improv classes and runs a satellite troupe in New York City.

Most of the company’s shows are presented in the style of TV’s “Whose Line Is It Anyway?” with two teams of three comics and a referee who act out skits based on audience suggestions.

Recently, the company has been expanding into long-form improv, where the cast creates an evening-length show with a specific theme, such as film noir, Shakespeare or (for Comic-Con week) science fiction.

National Comedy Theatre’s shows are billed as “clean,” except for the occasional midnight show when Kramer says “the gloves come off.”

“It’s clean, but it’s not Disney or Pollyanna. It’s like 9 p.m. television,” he said. “It’s an adult show, but it doesn’t use dirty language. For marketing reasons, you can reach a wider audience this way. And philosophically, it’s easy to go blue. You’ve got to work much harder and be much more clever if you’re not swearing.”

Kramer said that the formula for making people laugh has changed very little over the years.

“People are people. The sensibilities of the audience are the same,” he said. “Some of the pop-culture references have changed, but others are universal. Michael Jackson will never get old, and we still hear about Elvis.” Creating a comic